OVER
18 Appendix B: Specications (con’t)
Performance Over the Duration of Wear
This section presents the performance data in a variety of ways to demonstrate the performance of
the system over time during the entire sensor wear period. The sensor is worn on the body for up
to 5 days, during which time the system has to be calibrated 4 times. Typically, the system has to be
calibrated at 10, 12, 24 and 72 hours after sensor insertion. Data presented in this section demonstrates
how the sensor performs as a function of time.
Sensor Stability
Tables 6a-6b show there is little difference in accuracy over the five days of sensor wear according to
the Clarke Error Grid Analysis (Table 6a) and the Continuous Glucose-Error Grid Analysis (Table 6b).
Table 6a. Clarke Error Grid Analysis by day of wear
Zone Day 1 Day 2 Day 3 Day 4 Day 5
%%%%%
A82.5 82.4 79.4 84.0 80.9
B16.4 16.6 18.3 14.2 16.9
C0.2 0.1 0.0 0.0 0.0
D0.9 0.9 2.2 1.8 2.1
E0.0 0.1 0.0 0.0 0.0
Overall Mean Absolute
Relative Dierence (%)
MARD0
12.6 12.3 14.1 11.9 13.0
Table 6b. Continuous Error Grid Analysis by day of wear
Zone Day 1 Day 2 Day 3 Day 4 Day 5
%%%%%
Accurate
Readings 97.9 97.8 97.1 97.4 97.3
Benign
Errors 1.0 1.2 0.7 0.8 0.8
Erroneous
Readings 1.1 1.0 2.2 1.8 1.9
Table 6c groups the dierence between glucose results from the FreeStyle Navigator system and the
YSI into dierent blocks (within 20%, within 30% and within 40% from the YSI). It shows there is little
change in the dierence from YSI over time, thus demonstrating sensor stability.
Table 6c. Difference from the YSI at different times after sensor insertion
Time Aer Insertion
(hours)
Percent Readings
Within 20% of the
YSI*
Percent Readings
Within 30% of the
YSI*
Percent Readings
Within 40% of the
YSI*
10-12 86 92 96
12-24 82 93 97
24-72 81 92 97
72-122 82 93 97
*e absolute dierence from the YSI reading is measured in mg/dL if the YSI reading is at or below
75 mg/dL.
Section 18 157 Appendix B: Specifications